What Is a DNS Server?
To know about a DNS server, first, we need to elaborate on what a server is. A server is a device or software that provides services to other programs known as ‘clients.’ DNS clients, which are included in most current desktop and mobile operating systems, allow web browsers to communicate with DNS servers.
What is a DNS server?
The Domain Name System (DNS) is the Internet’s phonebook. When users input domain names like ‘google.com’ into web browsers, DNS is in charge of determining the correct IP address for those sites. Browsers then use the addresses to interact with origin servers or CDN edge servers to access website information. This is made possible by DNS servers, which are machines specialized in responding to DNS requests.
A DNS server’s goal is to convert what users put into their browser into something that a computer can understand and use to find a website. In other words, its function is to translate a domain name like www.example.com into an IP address like 220.127.116.11.
Thanks to DNS servers, people no longer have to memorize complicated IP addresses such as 18.104.22.168, Google’s IP address. They only need to remember www.google.com.
This translation process, known as DNS resolution, necessitates the use of many hardware components. The primary DNS server is the most critical.
How do DNS servers respond to DNS queries?
Four servers work together to send an IP address to the client in a standard DNS query without caching: recursive resolvers, root nameservers, TLD nameservers, and authoritative nameservers.
The DNS recursor (also known as the DNS resolver) is a server that receives the DNS client’s query and then communicates with other DNS servers to find the proper IP address. When the resolver gets the client’s request, it acts as a client, contacting the other three types of DNS servers in search of the correct IP address.
The resolver begins by querying the root nameserver. The root server is the initial stage in converting human-readable domain names into IP addresses (resolving). The root server then answers to the resolver by providing the address of a top-level domain (TLD) DNS server (such as.com or.net) that holds information for its domains.
The resolver then requests the TLD server. The TLD server returns the IP address of the domain’s authoritative nameserver. The recursor then contacts the authoritative nameserver, responding with the origin server’s IP address.
Finally, the resolver will return to the client the IP address of the origin server. Using this IP address, the client may then submit a query straight to the origin server, and the origin server will react by returning website data that the web browser can decode and display.
What exactly is DNS caching?
Recursive resolvers can resolve DNS requests utilizing cached data in addition to the procedure described above. The resolver will save the correct IP address for a particular website in its cache for a limited length of time after getting it. If any additional clients submit requests for that domain name during this period, the resolver can skip the regular DNS search procedure and just respond to the client with the IP address held in the cache.